The present invention relates generally to gas scrubbers of the venturi type and is more particularly concerned with a new and improved gas scrubber that incorporates an adjustable gas convector and demisting unit.
Today, more and more emphasis is being placed on the control of air pollution and the elimination of contaminants from the atmosphere. The air pollution problem is particularly acute in heavily industrialized and densely populated regions. For example, chemical and metal refining industries, foundries, metal manufacturing industries, and such, which have a large amount of waste gases either in the form of consumed gases or ventilating gases contribute extensively to air pollution. Unless these gases are treated adequately before being released into the atmosphere, humans may be subjected to dangerous and hazardous health conditions and the value of property, both personal and real, may be adversely affected.
As governmental agencies establish more rigid and stricter pollution standards for gases exhausted into the atmosphere, the need for more efficient, higher quality air pollution control devices has become acute and has led to the development of the invention herein described and claimed.
Gas scrubbers are a common means of removing gaseous and particulate pollutants from gases. A gas scrubber normally operates on the principle that a scrubbing liquid such as water sprayed into a stream of contaminated gas serves to wash the pollutants from the gas, the pollutants being carried away in the scrubbing liquid. However, during such scrubbing action, water droplets are entrained in the clean gas, and if allowed to remain therein, could be a source of contamination to the outside atmosphere because some of the pollutants being removed from the gas stream are carried in the droplets. Consequently, complex systems have been incorporated into scrubbers in order to reduce the entrainment of such droplets in the gas emitted from the scrubbers. In these systems the separated water is recirculated by means of pumps and piping back to the spray heads.
It has been suggested that gas scrubbers can eliminate pumps by driving the gas through or causes it to impinge upon a confined mass of water before passing through a venturi. This causes some breakdown or misting of the entrained water droplets. However, in these systems, the fine mist disadvantageously flows through the system and causes substantially the same contamination problems as with other systems unless appropriate filters are utilized.
It is the desideratum of this invention not only to eliminate the need for pumps and/or water sprays but also to provide automatic demisting coupled with adjustable control over the pressure differentials within the system.
An object of the present invention is to provide a new and improved venturi-type gas scrubber that includes simple adjustable control over the venturi throat opening and reliable self-contained demisting while obviating the need for pumps, nozzles, filters, spray chambers, piping and the like as well as the maintenance problems associated therewith.
Another object of the present invention is to provide a gas scrubber of the type described that is of compact economical design and well suited to simple, low maintenance requirements.
Still another object is to provide a gas scrubber that provides not only for impingement of the gas on a confined cleaning fluid and subsequent passage through a venturi passage but also for a static zone and a demisting unit operatively associated with the venturi passage for deflecting the heavy mist toward and into the static zone while permitting the clean gas to bypass the static zone.
A further object of the present invention is to provide a venturi-type scrubber of the type described that incorporates pumpless fluid injection into the venturi passage without the need for nozzles, piping and the like.
Other objects will be in part obvious and in part pointed out more in detail hereinafter.
These and related objects are accomplished in accordance with the present invention by providing a venturi gas scrubber comprising a liquid storage tank for holding a quantity of gas cleaning liquid and an elongated tower member having an open bottom end supported within the tank and immersed within the liquid. The tower has a gas outlet port adjacent the top thereof and a gas inlet tube extending centrally along the interior of the tower toward the gas cleaning liquid and adjustably mounts a gas convector and demisting unit. The unit includes a gas directing sleeve portion having a gas outlet end adjacent the surface of the liquid within the tank, an independently adjustable tubular venturi shroud partially immersed within the liquid and fully encircling the gas outlet end to provide an adjustable venturi constriction therebetween and a demisting flange circumscribing the sleeve intermediate the gas inlet tube and the constriction and extending outwardly from the tube well above the surface of the liquid but within the flow stream of the venturi constriction. In this way the liquid droplets accelerated through the constriction impinge on the flange and are deflected back toward the liquid within the bottom end of the tower while the gas travels toward the gas outlet port of the tower.
A better understanding of the invention will be obtained from the following detailed description and the accompanying drawings of an illustrative application of the invention.